The current invention relates to a system for distributing electrical energy over a cluster of electrical devices according to the preamble of the first claim.
The present invention also relates to a method for distributing electrical energy over a cluster of electrical devices of such a system and a controller for use in the system according to the invention.
Such systems are already known to the person skilled in the art. US2009/0228324 for example describes a smart grid for distributing electrical energy over a cluster of electrical devices, for example a cluster comprising all the electrical devices of a single household. The cluster comprises at least one smart grid participating electrical device, for example a dishwasher, a tumble drier, a washing machine, etc. all sporting some sort of flexibility with respect to the execution of the task assigned to them, such as for example when the task should be finished, and at least one smart grid non-participating electrical device, for example a television, a light bulb, etc. none sporting flexibility with respect to when their task should be finished as immediate performance of the task assigned is expected, for example showing moving images or lighting a room. The smart grid participating device is connected to an electrical grid through a smart grid by a smart grid agent. The smart grid agent is configured to determine the amount of electrical energy in function of time to be delivered to and from the electrical grid for the smart grid device of the cluster based on information, in the form of marginal demand functions, of the smart grid device and the smart grid. The system further comprises a meter for measuring the amount of electrical energy actually delivered to and from the electrical grid for the cluster, usually in the form of an electricity meter, in this specific case for example measuring the electricity delivered to and from the electric grid to the devices of the household.
However, according to such systems, the smart grid non-participating electrical device, when switched on, can for example immediately draw electrical energy from the electrical grid. However, the electrical energy in such a situation is not obtained through the smart grid using the smart grid agent but directly from the electrical grid such that more electrical energy is being drawn from the electrical grid than determined by the smart grid agent. Such situations can be very undesired as will be illustrated below.
For example, in a cluster comprising an electrical charging device, for example a battery, and an electrical producing device, for example photovoltaic elements, the smart grid agent can have determined that the electrical energy produced by the producing device is stored in the storing device. However, when suddenly a smart grid non-participating device, for example creating an unflexible load such as for example a light bulb, a television set, etc., is switched on, the electrical energy for that device is drawn directly from the electrical grid and not from the producing device, as it is often desired that the cluster consumes as much as possible its locally generated electrical energy. According to another example, suddenly an additional producing device is switched on such that the additionally produced electrical energy is not directed to charging the charging device but is instead delivered to the electrical grid, as it is often desired that the cluster consumes as much as possible its locally generated electrical energy.
Moreover, when the smart grid non-participating devices are not taken into account by the smart grid agent when determining how much energy should be drawn from the electrical grid, the determined amount of energy to be drawn from the grid by the smart grid participating devices could be completely wrong, for example even endangering the availability of electrical energy, as for example a lot of smart grid participating devices and/or smart grid non-participating devices requiring large amounts of electrical energy in, for example, short periods of time, would draw electrical energy from the grid without the smart grid agent knowing and therefore without the smart grid agent taking this use electrical energy into account.
Although it is possible to convert smart grid non-participating electrical devices to smart grid participating electrical devices, this requires the difference smart grid non-participating electrical devices to be all connected to the smart grid, usually requiring the hardware of the smart grid non-participating electrical devices to be changed, interconnecting the converted smart grid non-participating electrical devices to the smart grid, for example requiring new wiring or wireless connections. Such hardware conversion and interconnections with the smart grid are however very cumbersome to do and usually require a lot of work and even sometimes adaptations to the building in which the devices are located, especially when taking into account that a lot of the smart grid non-participating electrical devices are relatively small and inexpensive such as for example light bulbs, radios, etc.